In the field of containers and closures, there exist many containers having end closures designed to meet various consumer needs for dispensing foods, chemicals, and other various products. One such closure design is the rotary end closure disclosed in U.S. Pat. No. 2,954,148 to Corrinet, et al. Such a closure includes tamper evident, rupturable connections yet it provides an opening through which the contents of the container may ultimately be dispensed.
These rotor type end closures typically include a separate rotor movably attached to a base, with the base itself being attached to the end of the container by a convenient means such as an adhesive bond or a friction fit. The base generally includes one or more rupturable areas which, when broken, define one or more variously shaped openings or windows through which the contents of the container may then be dispensed. These rupturable areas preserve freshness prior to opening and provide evidence of tampering since the opening includes a rupturable connection that cannot be resealed. As disclosed in Corrinet, et al., this rupturable connection is provided in the form of frangible tabs on the base. These frangible tabs are helpful in securing the position of the rotor in a locked position which closes the dispensary openings provided in the base. This arrangement helps satisfy the consumer's desire to know that the contents of the container remain in the same condition they were in when the container was closed. If the tabs have been ruptured prior to purchase, adulteration may have occurred and the ruptured tabs provide evidence of rotor tampering.
The rotor generally includes openings matching those provided in the base. By manually rotating the rotor to a position where the rotor opening is aligned with the base opening, the contents of the container may be dispensed. In many of the known designs, the rotor is generally pivotally attached to the base by a centrally positioned hub or stem member. This stem can be part of either the rotor or the base and normally would allow the rotor to be snap-fit on to the base or be otherwise rotatably connected together. Alternatively, the rotor could be retained in place by an undercut peripheral edge as in Corrinet et al.
While the frangible tabs discussed above in Corrinet, et al. provide some indication that the package may have been tampered with by opening the closure in the normal manner, that is by rotating the rotor relative to the base, such a system does not provide any readily perceivable indication to the consumer whether the base and rotor have been pulled apart in some other manner or that the rotor may have been separated from the base without relative rotation. Thus, without rupturing the frangible member a tampering effort could still take place. In Corrinet, et al., when the rotor is pulled or raised vertically off the base, the opening 25 in the base is exposed and the contents may be adulterated through that opening. Once the rotor is reinstalled, there is no indication that the container has been tampered with since the rotor is merely snap-fit into the undercut edge provided about the periphery of the base upper surface.
Several designs, such as those disclosed in U.S. Pat. No. 4,541,541 to Hickman, U.S. Pat. No. 4,792,054 to Weidman, and U.S. Pat. No. 4,611,725 to Kacalieff, have all attempted to overcome this problem by providing closures capable of indicating attempts to tamper with the closure. Each of these designs employ a base and rotor combination utilizing a central hub as the pivotal connection therebetween. As a result, it would be up to the consumer to carefully study the hub of the end closure for any possible damage evidencing a tampering attempt. This may not be possible.
Still other closure structures are shown in U.S. Pat. No. 4,549,667 to Dullabaun, U.S. Pat. No. 2,780,395 to Schlabach et al, U.S. Pat. No. 3,239,111 to La Croce and U.S. Pat. No. 3,389,840 to Musel et al.